Edexcel C3,C4 June 2013 Thread

lol my friend does this strange method in working it out ... she said that you divide it by 2 because 4^1/2 is 1/2 so that why you do it. it sounds like a bunch of crap and she confused me? thats wrong , what she said right?

what do you think??

So, if anything from C1, C2 and C3 could come up in C4, does that mean I'll have to go over all the sequences and series and common ratio and sum to infinity stuff from C1 & C2?? Is there a chance of that coming up?? D:

Also, how would you integrate (cosx)^3 or (sinx)^3?

For C4 questions.. do the questions always tell you when to use integration by substitution?

Whether they tell you what substitution to use or not.. Do the question always guide you and say use the substitution method? Thanks!

I think if they don't say substituion, you can use anything.

I try to follow this process
1.trig identities (rearrange to get an easy integral)
then
2.check if substitution is possible (but usually I'd just skip this)
then
3.go with integration by parts, which usually guarantees to get you to the answer safely provided no mistakes are made

Okay thank you.. yeah integration by parts normally works when there are two functions and you let u= the correct thing.

Hope you don't mind me asking but for question 6 of the jan 2013 C4 paper... Why can't you integrate (1-2cos)^2 directly by increasing the power by 1 then dividing by the new power and then multiplying by -1/2?

Why do you have to expand out to 1 − 4cosx + 4cos^2x and the integrate (using trig identities)?

Thank you so much!

hey can you post the paper so I look at the paper or tell me where to find it??? thanks

if OG is 3 then OB is 1
if OB is b then OG is 3b

so OB is b (given)

GB=OG-OB
therefore 3b-b=2b

Question 4e)


Answer:
4e)



Getting a weird decimal for '+c'
Help?



Posted from TSR Mobile

Question 4e)


Answer:
4e)



Getting a weird decimal for '+c'
Help?



Posted from TSR Mobile

so when you separated the variables did you get

1/(1-y^2) dy = 1/2(1+x) dx

both side have integral sign?

I'm just latexing your post
"So when you separated the variables did you get

$\displaystyle \int\dfrac{1}{(1-y^2)} dy =\int \dfrac{1}{2(1+x)} dx$?"

what did you get for +c

3.486...

Hey,

Could someone help me with Q6c from C4 june 2012, the original paper not replaced one. (I only have paper copy sorry!) From ms I know now what to do and I'm ok with usually doing differential equations, but I didn't know that's what you were supposed to be doing for part c. If anyone could explain why and how I'd notice it because I didn't realise!
Thanks